The third shot is usually a booster shot, which can further increase the body’s antibody level and resistance to the New Crown Virus. After completing the full course of vaccination, the antibody level in the body of the vaccinated person will gradually decrease over time, and the resistance to the new coronavirus will also gradually decrease. At this time, a third booster shot is needed to further increase antibody levels and produce better protection, which is very effective in preventing infection and reducing the risk of serious illness. Currently, the third booster shot of the new crown vaccine is applicable to people who have completed the full course of inactivated new crown vaccine for 6 months or more, and after the completion of the third booster shot, the level of antibody is greatly increased compared with the second shot. Therefore, as long as there are no contraindications to vaccination, the booster should be given as soon as possible.